VFD in wire & cable industry

In the wire and cable industry, many processes begin with pay-off and end with take-up wire. In the part of pay-off wire, how to control the uneven tension is the urgent difficulty for many equipment design engineers and products control engineers. In the past electric design, the engineers used to adopt the A/D, D/A module of PLC, using PCB with tension control technique, and gain the pay-off speed by read the potential of potentiometer with tension swing bar. In this method to maintain a constant tension, it usually adopts the signal line from potentiometer with the tension swing bar and analog signal line from the D/A module which control the speed of the variable frequency drive (VFD). They are too long, that brings the signal distortion easily. Besides, take-up wheels with different axis diameter corresponds to inner parameters of PID of different PLC, if PID setting is not suitable, the pay-off line is easy to be unstable and the tension is hard to be constant, which will impact the quality of the product.

Technological requirement
As the forefront of a variety of equipment, power pay-off wire rack is widely applied in wire and cable industry. General speaking, the requirements as follows:

1. In wire and cable making industry, all wire after-processing has to be reeled round the plate tidily.
2. In the machinery process of start, stop, and working, the linear velocity of the wire and the take-up winder diameter both are not constant, but the linear velocity of the take-up machine and the linear velocity of the process machine have to be consistent.
3. While pay-off wire, the machine must track the linear velocity of the process machine automatically, and must adjust the rotate speed automatically based on the winder diameter, to keep the same with the process speed..
4. The pay-off speed auto-track the leading speed. The take-up speed auto-track the pay-off speed of the process machine. Auto-rollback while the wire is loose. Auto-stop for protection in breaking.
5. In the pay-off and rolling process, to maintain a constant wire tension.
6. When stable operation at a certain speed, the pendulum of the pay-off frame have to be stable.

Gozuk GK3000 drive is the unique VFD has this feature in domestic currently. Excellent control performance and good reliability also ensures the VFD drives superior performance in the cable industry.

Control of pay-off wheel and take-up wheel
The pay-off speed is depend on the take-up speed. Take-up wheel always experiences process of starting and slow-down to stop, which brings the pay-off wheel a non-constant speed. Meantime, wire and cable always change on the wheels. When the rotate speed is stable, the linear velocity is constantly changing. The take-up tension impacts the quality of the product directly. If the tension too large, the wire will be took-up too tightly. Slim wire is easy distorted and the inner filament is easy to be break. If the tension is too small, the take-up wheel will axially slip and dislocate while take-up the wire. The wire can’t be took-up tidily. So pay-off wheel have to adjust the speed of itself according to the balance position of the tension balance bar.

Diagram of the power pay-off and take-up wire rack

 
System configuration
Gozuk GK 3000 series drive is special VFD for power pay-off and take-up wire rack, with build-in braking unit, resistance installation according motor power.
Other accessories: Tension potentiometer, crown block, travelling block, and stop-bit magnetic switch.

VFD Features:

1. This VFD special for power pay-off and take-up wire rack is very easy to operate, no need to set the function parameter. Only need to connect the lines correctly, then it can work after power-on  
2. Automatic identification of rotate speed and direction. Auto-track the linear velocity, the tension balance bar usually maintains in the middle level.            
3. Whether big plate or small plate, thick or thin wire, high or low speed, tension is always constant.
4. Only need one wheel for winder, simplified machinery structure helps saving cost.
5. Build-in function for detect upper limit and low limit, No switch needed.
6. Easy for debugging: It is a separate part. No need extra signal, only need to adjust the position of tension detection potentiometer. It can auto-track the leading speed after power on.

 
Conclusion
Application of Gozuk VFD in wire and cable industry, have solved the electric control problem of power pay-off wire rack and take-up wheel in the industry. The line connection is simple. The VFD has PID and closed-loop control function itself, instead of the A/D, D/A modules and PLC programmed. Any common electric maintainer can operate it. Gozuk VFD should be the first choice of reform for old pay-off wire rack in wire and cable industry.